Liquid crystal display devices, which are characterized by very small thickness and low power consumption, are now widely used in various devices, such as notebook personal computers, cell phones, and smartphones. Recently, still lower power consumption has been demanded of the liquid crystal display devices.
As the technique for further reducing the power consumption of the liquid crystal display devices, intermittent driving (or “low frequency driving”) in which driving is performed with the image rewriting frequency (driving frequency) being lower than those employed in conventional liquid crystal display devices has been proposed (for example, Patent Document 1). In the intermittent driving, one frame includes periods where a display signal voltage (source voltage) is supplied to pixels and periods where no display signal voltage is supplied to pixels. In the latter periods (pause periods), it is not necessary to supply electric power to gate drivers and source drivers, resulting in lower power consumption.
However, decreasing the driving frequency (i.e., reducing the number of frames per unit time) makes flicker more readily perceivable. Perception of flicker deteriorates the display quality.
In view of such, Patent Document 2 proposes the technique of switching the mode of polarity reversal of the display signal voltage at the timing of switching between the normal driving and the intermittent driving (at the timing of switching the driving frequency). In a normal driving operation, a polarity reversal mode which requires small power consumption such as the column reversal mode is used, while in an intermittent driving operation a polarity reversal mode which provides an excellent flicker suppression effect such as dot reversal mode is used, whereby it is expected that both lower power consumption and high quality display can be achieved.